I think it’s possible to love God before salvation. Not everyone is attracted to God based on the offer of forgiveness and salvation. There are people who love God not for what He can do for them, but rather because God is a creator and a father. Their purpose in life is to serve God.
Do you remember when you loved someone deeply with agape love before you were saved? Did you require their gifts and blessings to maintain that love? Or was just being in their presence and talking with them enough? It’s the same with God.